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Introduction to Transcranial Doppler / TCD

Introduction to Transcranial Doppler / TCD. TCD and TCDI Principles. Objectives. List clinical applications for TCD Identify the architecture of the Circle of Willis Recognize data used for TCD interpretation Describe advantages of TCD imaging

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Introduction to Transcranial Doppler / TCD

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  1. Introduction to Transcranial Doppler / TCD

  2. TCD and TCDI Principles

  3. Objectives • List clinical applications for TCD • Identify the architecture of the Circle of Willis • Recognize data used for TCD interpretation • Describe advantages of TCD imaging • Identify TCD features of the MicroMaxxTM system

  4. Cervical Vascular Anatomy

  5. Cerebrovascular Anatomy

  6. Transcranial Doppler • Provides functional information about physiological flow states • Identifies anatomical location • Demonstrates the extent and degree of severity of various abnormalities

  7. American Academy of Neurology Position Statement (1989) • TCD is of established value in assessing • Servere stenosis of major basal arteries (>65%) • Collateral circulation • Vasoconstrictions • AVM’s • Brain Death

  8. TCD Utilization • Cardiology • Pre-operative extracranial carotid evaluation • Assessment of Intracranial collateral pathways • Emboli Monitoring

  9. TCD Utilization • Neuroradiologists • Trauma • Tumor/space occupying lesion • Aneurysm detection • AVM’s • Vasospasm • Brain death

  10. TCD Utilization • Vascular and Neurology Specialists • Assessment of intracranial collateral pathways in patients with extracranial carotid disease • Evaluation of response to revascularization • Evaluation of intracranial vascular lesion • Documentation of Subclavian Steal Syndrome • Assessment of Vertebrobasilar system • Monitor and manage Sickle Cell disease

  11. Understanding Non-Imaging TCD

  12. TCD-Non-Imaging TCD • Trace or map out the vessels only using the Doppler spectrum • Record bilateral depths and means equally • Compare vessels side to side, close to exact sample depths • Non-imaging is successful in 90% of the patient population

  13. TCDI-Imaging TCD • Advantages • Increased confidence in identification of vessels and pathology • Identification of anatomical variations • Quick identifications of abnormal flow patterns • Possibility of angle corrections • Disadvantages • Obtainable in 75-80% of the patient population

  14. A complete Circle of Willis is present in of the population 50%

  15. A perfect configuration of the Circle of Willis is present in only of the population 18%

  16. Vessel Identification Non-Imaging • Depth of Sample Volume • Direction of flow • Angle of transducer • Traceability of vessel • Spatial relationships between vessels • Response to CCA oscillations or compressions • All of these are utilized to “prove” what vessel you are insonnating

  17. Vessel Identification Imaging • Depth of Sample Volume • Direction of flow • Angle of transducer • Traceability of vessel • Spatial relationships between vessels • No need to “prove” vessels, because you can easily see where the vessel lie within the image

  18. Normal Values (Mean Velocities) VesselsMeanDepthFlow Direction MCA(M1)62+1230-67mmTowards ACA50+1160-80mmAway PCA39+1055-75mmTowards Siphon47+1460-80mmTowards/Away OA21+ 540-60mmTowards Basilar41+10>80Away Vertebral38+1060-85mmAway t-ICA39+ 950-60mmAway D-ICA37+ 935-70mmAway

  19. Investigator Variability AuthorMCAACAPCA Aaslid62+12 51+12 44+11 DeWitt62+12 52+12 42+10 Gromlimund57+15 49+15 37+10 Harders65+17 50+13 40+9 Ringlestein55+12 50+11 39+10 Zanette56+12 50+10 43+7 Sorteberg73+11 58+9 43+10 Russo65+13 48+20 35+18

  20. Physiologic Factors • Age • Gender • Hematocrit • Fever • Hypoglycemia • Carbon Dioxide • Heart Rate/Cardiac Output/Blood Pressure • Brain Activity

  21. Prior to TCD Exam • What is going on with the patients cerebrovascular and cardiovascular system? • Scan the patients carotid or have a recent carotid exam report • Find out if patient has had a recent echocardiogram

  22. Prior to TCD Exam Normal Exam

  23. Prior to TCD Exam Abnormal Exam

  24. Prior to TCD Exam Previous Patient Report

  25. Prior to TCD Exam Cardiac Mass

  26. TCD: Normal Direction of Flow

  27. TCD Imaging Orientation

  28. TCD & TCDI Protocol and Interpretation

  29. Access Windows Transorbital Window Transoccipital/ Suboccipital Window Transtemporal Window Submandibular Window

  30. TCDI-Transtemporal WindowBoney Landmarks Lesser wing of the Sphenoid Bone Lesser Wing Of the Sphenoid Bone Petrous Ridge Petrous Ridge Foramen Lacerum Foramen Lacerum Foramen Lacerum Foramen Lacerum

  31. TCDI-Transtemporal Window Segments recorded in a complete exam • MCA ( Prox, Mid, Distal ) • ACA • PCA ( P1 and P2 ) • tICA (Terminal ICA)

  32. TCDI- Submandibular Window Segments recorded in a complete exam • Distal ICA ( Internal Carotid Artery )

  33. TCDI- Suboccipital Window Segments recorded in a complete exam • Vertebral arteries ( Right and Left ) • Basilar artery ( Prox, Mid, Distal )

  34. TCDI- Transorbital Window Segments recorded in a complete exam • Ophthalmic Artery • Carotid Siphon Ophthalmic Artery

  35. TCDI-Transtemporal Window Low PRF Optimized PRF High PRF Be aware of your PRF settings when interrogating the Circle of Willis arterial segments

  36. TCDI-Transtemporal Window Low PRF Optimized PRF High PRF Be aware of your PRF settings when interrogating the Circle of Willis arterial segments

  37. TCDI-Transtemporal Window Low PRF Optimized PRF High PRF Be aware of your PRF settings when interrogating the Circle of Willis arterial segments

  38. TCD Interpretation

  39. Patients Clinical Presentation • SAH • Head injury • Tumor • AVM • Aneurysm • Extracranial vascular disease • Subclavian steal syndrome • Brain death

  40. TCD and TCDI Interpretation Criteria • MCA carries 80% of flow to the cerebral hemispheres • MCA mean velocities >ACA>PCA>Basilar >Vertebral • Normal mean velocities should be <90 cm/s • Mean velocities with mild vessel narrowing are >120c m/s

  41. TCD and TCDI Interpretation Criteria • Elevations in Mean Velocities may be due to: • Vasospasm – associated with trauma, SAH (subarrachnoid hemorrhage), aneurysm • Generalized increase in velocities • Changes over time • Stenosis – focal increase in velocity with PST • Collateral flow – associated with change in direction • Hyperdynamic flow – associated with head injury/AVM • Increased velocities in all vessels

  42. TCD and TCDI Interpretation Criteria • Pulsatility Index • Measures the peripheral resistance in the vascular bed • Absolute values alone are not very accurate, but changes in PI over time is an indicator of the severity of dilation • Normal = .9 – 1

  43. MicroMaxxTMPatient / Exam Type • TCD • High output power • Orbital • Low output power

  44. MicroMaxxTMDoppler Quantification • Auto Trace results • Fast and reproducible • Displays • TAP ( TCD mean ) • Peak Velocity • End Velocity • Pulsatility Index • Resistive Index • Systolic/Diastolic Ratio • Doppler Gate Size • Sample Volume Depth • Manual Trace also available

  45. MicroMaxxTM TCD Report Pages

  46. Summary • MicroMaxxTM offers the clinician a complete cardiovascular imaging system • Small, portable system easily taken to patients’ bedside • TCD and Orbital exam types • Comprehensive report package • High-end application on an affordable system

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